I think during 4.2 I did some tests for my collage presentation. I used flocking algorithm for AI. I had group of agents starting in a dispersed formation and on a button trigger they would start the flocking.
Difference was around 117fps (C++) vs 72fps (BP) during calculations (they were calculating every frame until position in flock was reached). Maybe its not 10x better, but I would say the difference in performance for calculating heavy things is still painful in BP. Your tests seem totally accurate 
thanks for doing them @! its nice to compare them with my results 